Previously, detergents used for washing of clothes, etc., were being compounded with detergent builders (detergent aids) such as zeolite, carboxymethylcellulose, polyethylene glycol, etc., for the purpose of improving the washing effects of detergents.
In addition to various detergent builders described above, detergent compositions have been being compounded with polymers as a detergent builder.
For example, it has been reported to use (meth)acrylic acid-type polymers comprising (meth)acrylic acid-type monomers, 2-hydroxyethyl(meth)acrylate, C2-12 alkyl(meth)acrylate and/or vinyl aromatic monomers in detergent builders and detergent compositions (e.g., refer to Patent Reference 1). The copolymer compositions described in the above patent reference 1 are disclosed to have effects of effective removal of hydrophobic dirt and stains of clothing such as collar dirt, oily stains, etc., and excellent resoil inhibiting ability preventing the dirt or stains once removed from reattaching to the washings even if the washing is carried out with a small amount of water.
Furthermore, it has been also disclosed to use polyalkylene glycol-type polymers having a glycidyl ether-origin hydrophobic site inside the chain and/or at the chain end, monomer unit derived from a polyalkylene glycol-type monomer with a polymeric double bond of an isoprenol, allyl alcohol or methallyl alcohol origin and at the same time, carboxylic acid group and/or sulfonic acid group as a detergent builder (refer to Patent Reference 2). In the patent reference 2, the above polymers have been disclosed to have a performance inhibiting precipitation of the surfactant and/or ability inhibiting resoiling with dirt removed once at the time of washing (called resoil inhibitory ability).
Furthermore, as a property presently required for detergent builders, there are not only abilities improving the detergency of detergents but also performance inhibiting or preventing any precipitation of the surfactant (it may be called simply precipitation inhibitory ability, below). In this case, the problem of surfactant precipitation is apparent as a result of bonding of anionic surfactants, for example, straight chain alkylbenzenesulfonic acids (salt (LAS) such as dodecylbenzenesulfonic acid (salt), etc., with calcium or magnesium ion present in water when the washing is carried out with water of relatively high hardness (refer to Non-patent Reference 1).
As an art improving the precipitation inhibitory ability, there is a technique disclosed in Patent Reference 3. In the patent reference 3, a graft copolymer of a hydrocarbon group-containing polyoxyalkylene compound with a specific amount of an acid group-containing unsaturated monomer graft-polymerized is shown to exhibit an excellent performance as a detergent builder.